/Engine/Plugins/Experimental/PlanarCutPlugin/Source/PlanarCut/Public/PlanarCut.h
Merge all chosen nodes into a single node. UnlikeMergeBones(), does not account for proximity and will always only merge the selected bones.
void MergeAllSelectedBones ( [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) & Collection, const [TArrayView](API\Runtime\Core\Containers\TArrayView)< const int32 > & TransformIndices, bool bUnionJoinedPieces )